[SteviGX]

alright, so here's the story. A buddy of mine took his car to a shop out here in IN to get an anderson powerpipe and a 8 rib system put on his car. It's a forged block, vt stage 2 heads, with some nasty ground comp cams, all that good stuff. The cars built. Well, when he went to pick the car up, it started to make some hellacious noise. He checked the heads and he said that all the valves sound the same so he doesn't think it's in the top end. What could make a loud like clunk noise in the lower end on these cars. I tried to help him but i'm not a specialist on these things and any help would be greatly appreciated!

CliffNots:
Motor Knock
Built lower and Boosted
Eliminated Top End


Timing?
Piston rings?
Anything?
???

[dude496]

Well he did get a power pipe installed....did he get it re-tuned? Any adjustment in air flow can cause knock.

highly doubt rings....you would def know that was a problem, car will run rougher

Timing see above...

Not enough fuel will cause knock

[SteviGX]

Yeah, the retune was done by Bob Kurgan. But the more i read about it I'm seeing that timing could be a major issue. He has an A/F ration gauge but wasn't paying attention. I'm hopnig to get out there tommorow to check it out in person.

Thanks for the help dude. He said it was running fine, there just was the knock sound and little bit of a misfire through the exhaust but he said you could really hear the knock thorugh the exhaust

[dude496]

Is it a wide band a/f? Since he had it retuned, they should have provided an a/f chart.

Any sounds that are other than normal mean time to shut down till figuring out what is wrong....what could be simple now can turn very costly very quick.

What do you mean by only hearing it through the exhaust??? Like someone put their ear up to the tail pipe to hear the knock or only heard it while revving it up???